edited by Peter Cowie
Hamlyn, 1995
Buku Referensi
by Ernst & Young
Kogan Page, 1995
Buku Teks SO
J.B. Kristanto
Kompas, 2004
Buku Teks
by United Nations Children's Fund
UNICEF, 1995
Buku Teks
Anderson, Joseph L.
Rutland Charles E Tuttle 1959
Buku Teks